الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 386 |  |  |
| | | from | 386 | | |
Abstract
In Egypt, Grapes are the second most important fruit crops. They come after citrus fruits. Average cultivated area with grapes vines increased from 84.509 Feddan in 1989 to 141.233 in 2000 with an increase of 67 % on the cultivated area. Also the production increased from 606.845 ton in 1989 to 1009.563 tons in 2000, with an increase of 66 % over the same period (MALR, 2000). Drying with the various forms of traditional sun drying. These factors include product pollution from dust, and animal contamination, a large production losses due to inadequate dehydration, or/and product infestation and spoilage. Drying in industrial air dryers is good alternative in order to attain a good quality for the final product. The main objective of the present study was to develop and evaluate a small scale industrial portable grapes dryer suitable for small and medium grape farms and using butane gas as heat energy source. The laboratory experiments were conducted at three different level of drying air temperature (50, 60 and 70 <U+F0B0>C), two levels of air velocity (1 and 2 m/s), and three levels of air relative humidity (15, 25 and 35 %). However, for the field experiments, a develop portable dryer using butane gas as a heating source was used. The temperature of drying air was adjusted to be at selective levels of 50, 60 and 70 <U+F0B0>C respectively. And the air velocity was adjusted at levels of 1 and 2 m/s. The following results could be down out for both laboratory and field experiments are as follow: 1 All the studied models could describe the drying behavior of grape satisfactory as indicated from the higher correlation coefficients for all models which ranged from (0.9452 to 0.9898). On the other hand, the Page?s model could be considered the most proper model for describing the drying behavior of grape and predicting the change in moisture content during the laboratory drying process. While, the modified simple model could be considered the most appropriate model for predicting the change in moisture content of grape during the field experiments using the proposed portable dryer followed by the Page model. 2 The higher drying air temperature of 70 <U+F0B0>C and air velocity of 2 m/s give the best organoliptic characteristics of the dried grape due to the lower enzymatic browning and also the lower final moisture content of the dried grape. 3 The thermal efficiency of the portable dryer could be considered satisfactory for general use. Also the dryer with the present capacity of (20 kg/run) could be considered a good project for small farmers with net profit of (3130 LE/season) and its economic feasibility could be increased by increasing the capacity and the operation hours throughout the year through drying more than one crop.